I recently got a water simulation using particles (1000-1500) working (using the stokes equation), but my problem is that I use a IDXSprite which just draws the particles using blue texture quads (7x7), that doesnt look very smooth.
Is there any way or known technique for drawing such systems so the surface will look smooth (and the water shouldnt have the edges from the textures in it)
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How to smooth geometry with morpher attached in SceneKit or Unity 3D? I heard that average the normal of vertices will work but I have no ideal how to do it.
For example I have a rough sphere like this, How can I smooth it by changing normal of vertices? subdivisionLevel doesn’t works because there are some morpher animations on it.
From Apples class reference for SKShapeNode's but also from many developers i hear that using SKShapeNode for drawing custom shapes you want to draw often on the view is a bad idea because it performs bad.
Its true, a simple app with some custom shapes is spiking my CPU up to 80% and using like 80MB RAM (on devices its a bit better).
So then, how do i draw shapes like arrows without using SKShapeNode, because i like the idea to draw with bezierpaths since i do not need to care about display size.
How to draw an arrow with a texture without getting a bad quality, since it would stretch my image when i move my touch stretching the arrow. Doing this with SKShapeNode works perfect but performs bad.
You can always have one SKShapeNode node available that you use for creating shapes, and use the path property to design the shape. Then create a texture out of the SKShapeNode from the scenes view with let texture = scene.view.textureFromNode(shapeNode) and place the new texture into an SKSpriteNode
I have been able to convert a 3D mesh from Maya into Voxel art (looks like a bunch of cubes--similar to legos), all done in Maya. I plan on using the 3D art to wrap around my 2D textures to make it 2.5D. My question is: does the mesh being voxelized allow me to use the pieces as particles that i can put into a particle engine in XNA to have awesome dynamic effects?
No, because you get a set of vertices and index defining triangles with no information about cubes.
But you can create an algorithm that extract the info from the model. It's a bit hard but it's feasible.
I'd do it creating a 3d grid, and foreach face I'd launch rays from that face to the opposite face, taking every collision with the mesh, getting for each ray a number of collisions that should be pair (0, 2, 4,...), this between two points should have a solid volume.
That way it can be converted to voxels... on each collision it would be useful to store the bones that are related to the triangle that collides, this way you would be able to animate the voxel model.
Hi there, the effect I want to implement is burning out user's signature. I've done the signature drawing with quartz2D. Can any one show me a direction for drawing the burning glow effect? thanks!
The glow is caused by light streaming from a source through the strokes and illuminating particles in the air as it travels.
So a brute-force solution that works when viewed directly from the front is to draw the plane several times with additive transparency. You'll want to move and scale the plane for each draw so that you're tracing out the shape of a frustum.
You'll need to do so many draws that I can't imagine you'll end up with both real-time performance and an acceptable result. You should be fine if you can spend a second or a half-second or so on preparing the image on e though.
The most obvious alternative would be to work backwards, writing a shader that traces back through the frustum, sampling the 2d texture appropriately. That's likely to cost a similar amount because texture sampling will be the bottleneck due to memory bandwidth (make sure you upload as a one-channel texture in any event), but could be done so as to work from any angle.
I am currently working on a 2D "Worms" clone in XNA, and one of the features is "deformable" terrain (e.g. when a rocket hits the terrain, there is an explosion and a chunk of the terrain disappears).
How I am currently doing this is by using a texture that has a progressively higher Red value as it approaches the center. I cycle through every pixel of that "Deform" texture, and if the current pixel overlaps a terrain pixel and has a high enough red value, I modify the color array representing the terrain to transparent. If the current pixel does NOT have a high enough Red value, I blacken the terrain color (it gets blacker the closer the Red value is to the threshold). At the end of this operation I use SetData to update my terrain texture.
I realize this is not a good way to do it, not only because I have read about pipeline stalls and such, but also because it can become quite laggy if lots of craters are being added at the same time. I want to remake my Crater Generation on the GPU instead using Render Targets "ping-ponging" between being the target and the texture to modify. That isn't the problem, I know how to do that. the problem is I don't know how to keep my burn effect using this method.
Here's how the burn effect looks right now:
Does anybody have an idea how I would create a similar burn effect (darkening the edges around the formed crater)? I am completely unfamiliar with Shaders but if it requires it I would be really thankful if someone walked me through on how to do it. If there are any other ways that'd be great too.
Sounds like you're good in the right way. But you're doing a lot of things by hand, which can also be done by just drawing sprites and applying the right formulas.
For example:
Suppose your terrain is saved into a giant texture in the alpha channel of the texture. 1 is terrain, 0 is nothing.
An explosion happens and the terrain has to be deformed. Update your texture easily by just drawing a black transparent sphere (or explosion area) onto your texture. The terrain is gone, because the alpha value is 0 of the black sphere. Your texture is now up to date, everything was done by the spriteBatch. And nothing had to be checked.
I don't know if you wanted a solution for this as well, but now you have one.
For the burn effect
Now that we have our terrain in a texture, we can do a post effect on the drawing by using a shader (just like you said). The shader obtains the texture's alpha channel and can now do different things to get our burn effect.
The first option is to do edge detection. Check a few pixels in all 4 directions and see if the pixel is at the edge. If so, it needs to do a burn by, for example, multiplying it with the distance to the edge (or any other function you like)
Another way is quite similar to the first one, but does it in two steps. First you do the same kind of edge detection, but you save the edges in a seperate texture. Now, when you are drawing your texture, you can overlay your edges. So it's quite the same as just drawing the ground at once.
The main difference for the second option is that you can also choose to just draw your normal ground and you are not adjusting the pixel in the ground texture on rendering.
I know this is a long story, but it is a nice technique. Have a look at toon shaders, they do edge detection as well, even though it is 3D.
Keywords: Toon shading, HLSL, Post effects, edge detection, image processing.
Recommended reading: http://rbwhitaker.wikidot.com/xna-tutorials